A drilling head with a cone rock bit, each cone having a stationary part and a rotary part which rotates about an axis of rotation. Also included is a dynamic sealing device between the stationary part and the rotary part. The sealing device is borne by the rotary party and has a first sealing lip and a second sealing lip, each of which forms a surface of revolution about the axis of rotation. Further, the first and second lips bear respectively against a first bearing face and a second bearing face secured to the stationary part. The first lip is oriented in such a way that it presses against the first bearing face under the action of the pressure, and the second lip is oriented in such a way that it moves away from the second bearing face under the action of the pressure of the lubricating product, so as to allow this product to fill a cavity and compensate for the pressure in the cavity.
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1. A drilling head, comprising:
a cone rock bit, each cone including: a stationary part including a pressure-compensating system configured to deliver a lubricating product at a desired back pressure to compensate for apressure of a drilling matter; a rotary part configured to rotate about an axis of rotation; and a dynamic sealing device borne by the rotary part and being disposed between the stationary part and the rotary part, and configured to avoid an ingress of drilling matter under said pressure of the drilling matter, and said sealing device including: a first sealing lip having an outer face facing toward said drilling matter and an inner face facing toward a cavity which forms a reservoir of the lubricating product; and a second sealing lip having an outer face facing toward an outlet of the pressure compensating system at said back pressure and an inner face facing toward said cavity, wherein the first and second lips form a surface of revolution about said axis of rotation, and respectively bear against a first bearing face and a second bearing face secured to the stationary part, wherein the first lip is oriented in such a way that it presses against the first bearing face under the action of the pressure of the drilling matter, and wherein the second lip is oriented in such a way that it moves away from the second bearing face under the action of said back pressure of the lubricating product, so as to allow the lubricating product to fill the cavity at said back pressure thereby compensating for the pressure in the cavity.
2. The drilling head according to
wherein the second bearing face includes a track defined by a cylinder, the axis of which is the axis of rotation of the cone.
3. The drilling head according to
4. The drilling head according to
wherein at least one of said first and second lips has an extension which forms a static seal between the first armature and a wall of the rotary part.
5. The drilling head according to
wherein the second armature has a static seal configured to form a static seal between the second armature and the stationary part.
6. The drilling head according to
a third sealing lip with an outer face facing toward said drilling matter, and an inner face facing toward the outer face of the first sealing lip.
7. The drilling head according to
a multiple-pole magnetic encoder and a sensor facing one another, one of which is borne by the stationary part and the other of which is borne by the moving part.
8. The drilling head according to
9. The drilling head according to
10. The drilling head according to
11. The drilling head according to
12. The drilling head according to
13. The drilling head according to
wherein at least one of said first and second lips has an extension which forms a static seal between the first armature and a wall of the rotary part.
14. The drilling head according to
wherein the second armature has a static seal configured to form a static seal between the second armature and the stationary part.
15. The drilling head according to
a third sealing lip with an outer face facing toward said drilling matter, and an inner face facing toward the outer face of the first sealing lip.
16. The drilling head according to
wherein at least one of said first and second lips has an extension which forms a static seal between the first armature and a wall of the rotary part.
17. The drilling head according to
18. The drilling head according to
19. The drilling head according to
a third sealing lip with an outer face facing toward said drilling matter, and an inner face facing toward the outer face of the first sealing lip.
20. The drilling head according to
a multiple-pole magnetic encoder and a sensor facing one another, one of which is borne by the stationary part and the other of which is borne by the moving part.
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1. Field of the Invention
The present invention relates to a drilling head with a cone rock bit.
2. Discussion of the Background
A rock bit of this kind is generally fitted with three cones and is in fact known by the name of a three-cone bit and is intended to be used, in particular, for deep boreholes, for example going down 3000 to 4000 meters or even more.
The drilling head has to operate under arduous conditions, that is to say in the presence of an abrasive drilling sludge and strong vibration, at a pressure often in excess of 400 bar (for the aforementioned depths) and at temperatures which may exceed 150°C C.
One of the crucial aspects of the rotary cones is their dynamic seal which has to remain effective under the aforementioned conditions.
There are currently two types of seals in existence which are used in the envisaged application, namely toric seals and metal-metal seals.
Drilling heads employing one or more toric seals are described, in particular, in American Patents U.S. Pat. No. 4,623,028 (Reed Tool Company), U.S. Pat. No. 5,456,327 (Smith International) and U.S. Pat. No. 5,129,471 (Hughes Tool Company).
Seals of the metal-to-metal type generally exhibit better life than toric seals. Seals of this type are described, for example in European Patent Application EP 138 737 (Hughes Tool), in American Patents U.S. Pat. No. 4,344,629, U.S. Pat. No. 4,824,123 and U.S. Pat. No. 4,822,057, all three of these being in the name of Smith International Inc., U.S. Pat. No.4,838,365 (Reed Tool Company) and U.S. Pat. No. 4,306,727 (Reed Rock Bit Company).
The problems posed by the design of this kind of seal have been set out in the article by Mike Hooper and Mark Hommel which was published in the minutes of the ASME Winter Annual Meeting, Dec. 1-6, 1991, Atlanta-Ga., under the reference 91-WA-DE-11 (p. 1-11) of The American Society of Mechanical Engineers (345 E. 47 St. New-York N.Y. 10017).
The subject of the present invention is a drilling head with a cone rock bit, in which a cone is sealed by a device which may be made of elastomer and which affords better performance by comparison with the toric seals.
Another object of the present invention is for sealing to be provided by a device which has a long life.
Another object of the invention is to allow the moving part to have an amplitude of deformation or even angular dislocation without the sealing being affected.
Another object of the present invention is for the sealing to be accompanied by effective consideration given to the back pressure generated by a pressure-compensating system.
Another object of the present invention is for the sealing to be easily fit into the cone.
At least one of the aforementioned objects is achieved, according to the present invention, by a drilling head with a cone rock bit. Each cone has a stationary part and a part which rotates about an axis of rotation. Also included is a dynamic sealing device between the stationary part and the rotary part, which is intended to avoid the ingress of drilling matter. The stationary part includes a pressure-compensating system capable at its output of delivering a product for lubricating the seal at a desired back pressure. Further, the sealing device is borne by the rotary part and has a first sealing lip and a second sealing lip, each of which forms a surface of revolution about the axis of rotation.
In addition, the first and second lips bear respectively against a first bearing face and a second bearing face secured to the stationary part. The first bearing face includes, for example, a track defmed by an annulus, the axis of which is the axis of rotation of the cone, and the second bearing face includes, for example, a track defined by a cylinder, the axis of which is the axis of rotation of the cone. The first sealing lip also has an outer face facing toward the drilling matter and an inner face facing toward a cavity which forms a reservoir of lubricating product. The second sealing lip has an outer face facing toward the outlet of the pressure-compensating system and an inner face facing toward said cavity. Further, the first lip is oriented in such a way that it presses against the first bearing face under the action of the pressure, and the second lip is oriented in such a w)ay that it moves away from the second bearing face under the action of the back pressure of the lubricating product. This allows the product to fill the cavity and compensate for the pressure in the cavity, particularly between the outer and inner faces of the first lip.
The first and/or the second sealing lip are advantageously made of elastomer. The second lip may have an annular bulge with a double chamfer forming a sharp edge which makes the seal.
At least one lip advantageously has a backing spring, for example a spring with prestressed turns constituting a toric annulus.
According to a preferred embodiment, the first lip and the second lip are borne by a first armature that revolves about the axis of rotation and which is secured to the rotary part. Further, at least one of the first and second lips has an extension which forms a static seal between the first armature and a wall of the rotary part. The first armature may consist of a single piece or alternatively may be made up of at least two parts joined together.
According to a particularly advantageous embodiment, the first bearing face and the second bearing face form part of a second armature consisting of a part that revolves about the axis of rotation and which is secured to the rotary part. Further, the second armature has a seal which makes a static seal between it and the rotary part.
The drilling head may also have a third sealing lip with an outer face facing toward said drilling matter and an inner face facing toward the outer face of the first sealing lip. dr
Other features and advantages of the invention will become more apparent from reading the description which will follow, which is given by way of nonlimiting example in conjunction with the drawings in which:
As shown in
This piece of armature 50 has a leg 51 at right angles to the leg 54 and which is push-fitted (for example using a ram) onto a cylindrical region 61 of the stationary part 1, with the insertion of an elastomer seal 60 which forms a static seal.
The seal 10 has a second sealing lip 13 which has a cuff 16 and a heel 26 with one face 19 facing toward the cavity 40, and one face 18 facing toward the duct 5, the faces 18 and 19 delimiting a circular sealing sharp edge 17 between them. Furthermore, a spring 20, for example a spring with prestressed turns closed up on itself so as to form a toric annulus, is mounted in a groove in the lip 13 and held in place by a retaining upstand 21. This spring allows the lip 13 to be pressed against the bearing face 52 of the metal armature 50. The lip 11 may also have a spring 201, which may be of the same type as the previous one and which presses on the face 14 to press the contact region 12 against the face 56.
The heel 26 of the lip 13 has a catching upstand 23' on the short leg 32 of a piece of armature 38 which in section is L-shaped and the main leg 31 of which is push-fitted by its cylindrical outer face 36 onto the internal face of the region 34 of the metal armature 30.
As the sealing lip 13 faces toward the cavity 40, an increase in pressure in the duct 5 tends to exert force on the face 18 to lift the sharp edge 17 away from the bearing face 52 and leave a free passage for the lubricant to allow it to fill the cavity 40 and thus lubricate the sealing lip 11.
If the pressure in the duct 5 exceeds the pressure of the drilling sludge, the lubricant tends to lift the lip 11 off its bearing face 56 and emerge in the direction of the groove 4.
By contrast, if the pressure of the lubricant drops below that of the drilling sludge, the lip 11 exerts its positive locking function, while the cavity 40 remains full of lubricant and constitutes a reservoir capable of ensuring continuous lubrication of the active parts 12 and 17 of the lips 11 and 13.
The embodiment of
For this purpose, the leg 54 has an extension 71 which increasees the area of the face 57 and therefore the bearing areaof the lip 70.
The seal in
The seal in
Besson, Alain, Fayaud, Patrick, Tissier, Bernard, Lecour, Pierre
Patent | Priority | Assignee | Title |
6568684, | May 04 2001 | Caterpillar Inc. | Method of forming a seal assembly around a shaft |
6729623, | Jul 19 2000 | RFT S P A | Sealing assembly for two relatively rotating members, in particular the two rings of a rolling-contact bearing |
7267186, | Aug 26 2005 | Baker Hughes Incorporated | Magnetic face seal for rock drill bit bearings |
8955849, | Jun 04 2012 | Federal-Mogul LLC | Radial shaft seal and assembly therewith |
9091130, | Feb 13 2013 | VAREL INTERNATIONAL, IND., L.P. | Rock bit having a radially self-aligning metal faced seal |
9157280, | Feb 08 2013 | BAKER HUGHES HOLDINGS LLC | Enhanced backup ring features for metal face seal in roller cone drill bits |
9163458, | Feb 13 2013 | VAREL INTERNATIONAL, IND., L.P.; VAREL INTERNATIONAL, IND , L P | Rock bit having a flexible metal faced seal |
9163459, | Feb 13 2013 | VAREL INTERNATIONAL, IND., L.P.; VAREL INTERNATIONAL, IND , L P | Rock bit having a pressure balanced metal faced seal |
Patent | Priority | Assignee | Title |
3529840, | |||
3682488, | |||
3944306, | Dec 16 1974 | Smith International, Inc. | Rock bit bearing seal |
4262759, | Sep 24 1979 | Dresser Industries, Inc. | Combination seal and pressure relief valve for sealed drill string unit |
4289321, | Feb 27 1979 | Stemco Inc; COLTEC NORTH CAROLINA INC | Pressure shaft seal and method |
4298079, | Mar 28 1979 | Sandvik Aktiebolag; Aktiebolaget SKF | Rotary drill bit |
4344629, | Oct 14 1980 | Smith International, Inc. | Self-lapping high speed seal with wear-in lip |
4981303, | Oct 25 1988 | NOK Corporation | Sealing device |
5015001, | Jul 23 1990 | Federal-Mogul World Wide, Inc | Low friction seal assembly |
5027911, | Nov 02 1989 | Dresser Industries, Inc. | Double seal with lubricant gap between seals for sealed rotary drill bits |
5167419, | Oct 22 1991 | Freudenberg-NOK General Partnership | Fluid seal with integral check valve |
5244215, | May 10 1985 | SKF USA INC | Rotary shaft seal with retractable excluder lip |
5458420, | Dec 10 1993 | MPB Corporation | Bearing seal with encoder |
5513715, | Aug 31 1994 | Dresser Industries, Inc | Flat seal for a roller cone rock bit |
5553870, | Feb 16 1994 | MPB Corporation | Lip seal separating oil and grease |
DE19614946, | |||
DE4107678, | |||
GB2101238, |
Executed on | Assignor | Assignee | Conveyance | Frame | Reel | Doc |
Mar 14 2000 | BESSON, ALAIN | Hutchinson | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 011040 | 0277 | |
Mar 14 2000 | BESSON, ALAIN | Total | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 011040 | 0277 | |
Mar 23 2000 | Hutchinson | (assignment on the face of the patent) | ||||
Mar 23 2000 | Total | (assignment on the face of the patent) | ||||
Apr 05 2000 | LECOUR, PIERRE | Hutchinson | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 011040 | 0277 | |
Apr 05 2000 | LECOUR, PIERRE | Total | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 011040 | 0277 | |
Apr 10 2000 | TISSIER, BERNARD | Hutchinson | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 011040 | 0277 | |
Apr 10 2000 | TISSIER, BERNARD | Total | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 011040 | 0277 | |
Apr 11 2000 | FAYAUD, PATRICK | Hutchinson | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 011040 | 0277 | |
Apr 11 2000 | FAYAUD, PATRICK | Total | ASSIGNMENT OF ASSIGNORS INTEREST SEE DOCUMENT FOR DETAILS | 011040 | 0277 |
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